The Dark Devil Sky
by tigrun
Summary: The betrayed sky is revived into the world as a devil. Kuroka, as his accomplice, asked him to watch over Koneko. His duty is to observe that little kitten not to befriend any of those morons, but as the time passes, who know what will happen. Maybe will he heal from his awful experience or will he stay the same? Dark!Tsuna Betrayed!Tsuna Broken!Sky cowritten with NonaryNathan999
1. Chapter 1

**I do not own Katekyo Hitman Reborn and High School DxD. I only own this story.**

How dare he?! How dare he think of using her dear sister?! She was the most important person in an entire life. She won't let anyone take advantage of her dear sister. She will make him pay for that.

Kuroka angrily though this as went to her 'King's' place. She was ready to prepare to kill to protect her dear little sister. That bastard was planning to use little Shirone for an experiment. It didn't matter that that man had taken them off of the streets and gave them food, clothing, a place to call home. The sick devil was going to regret his decision.

She made sure not to be notice by anyone as she went to do the worst thing she would ever do in her entire life. She may regret this decision later but she couldn't let her sister be hurt by her ignorance and her indecision. Shirone was the only family she had left.

As she came close, she heard some laughter from her _dear_ king, he laughed as a mad man for some reason. She heard him say: "You were one of the greatest skies to be, and yet here you lie; betrayed. How do you feel about... second chances?"

Hearing laughter, Kuroka then saw an array of lights dancing from around the corner she was hiding behind. The very objects that littered the room began to rise while power filled the air. Temperature was rising, even causing Kuroka to sweat within seconds.

"Now rise, and serve me." Her King commanded, making wild gesture to the corpse. "RISE! AND! SERVE!"

There was a grunt. Then a growl. "I... serve... NO ONE!"

The voice seemed so powerful and emitted even greater heat. Kuroka was beginning to sweat bullets. She peeked around the corner she had her back to to see who was the individual with curiosity. But the only thing that filled her sight were flames that covered a young man, that seemed almost the same age as her sister, maybe little bit older... or even younger? She couldn't tell because of his not very tall height. The flames were orange but also held a dark color, almost black. Those black flames emitted a lot of magic. Kuroka shivered by its intensity as she didn't realize that she had stepped out from her hiding spot to get a better view.

"What do you mean you serve no one?" Their king asked outrage. "I have summoned and revived you giving you another chance! YOU WILL SERVE AND OBEY ME!" He screamed at him as he prepared to use demonic magic on his new subject.

He sent his spell towards the individual whose flames seemed to be more intensive and more dangerous as it began to cover his all body. The spell was dissolved by the flame that moved defensively to protect the boy. It was as if they were alive.

The king was perplexed in front of his spell not working. This person was supposed to be his masterpiece, his puppet, his queen piece that would destroy any enemies in this path. "NO! NO!" The king yelled in frustration and rage but it turned into a slight bit of fear as he noticed that the brunette had been walking towards him. "YOU MUST OBEY!"

The boy grabbed the one who resurrected him by the throat. He glared directly towards the Devil's eyes with a cold expression. It was almost so... neutral without a single shred of remorse. He heard the choking but didn't loosen his grip. "The dead only wish to rest." He stated as he threw his victim against the wall.

The body that was tossed against the flat surface fell onto a desk that was filled with all sorts of papers. The sheets scattered around the area as the Devil groaned while glaring. He then noticed Kuroka out of his eye. "You! What are you standing there for?! Kill him!"

Kuroka could only watch as the boy craned his head slowly over towards her direction. Walking around to avoid being in his line of sight, the youkai saw that her 'King' was getting back up already, preparing some sort of flame spell by the look of things. But that was when she remembered her objective. Rushing forward, she dashed right past the boy and punched her King right in the stomach. With the power of Senjutsu and Youjutsu, it was a devastating blow meant to kill.

The Devil doubled over in pain, falling to his knees. Coughing, he spat out blood violently while grinding his teeth. "You bitch! You betray me too?!" He exclaimed as the spell he had been preparing against the boy was about to be thrown towards her.

A single foot came from above however and aimed the spell right towards the floor.

Kuroka was blown away from the blast, but the 'King' was not as lucky. The strength in that spell combined with how close he was provided to be too much for the body to handle as the Devil was nothing more than a corpse within the room. Only the person who had been resurrected recently was standing right in the place where Kuroka and the corpse were a few seconds ago. There was no glee or anger in his features, just a downcast look.

Kuroka was awestruck by what the man did, but quickly understood that they needed to escape before people caught him. She owed him at least that, he just saved her precious little sister… That's right, she had to still-

Voices were soon heard. There were coming and there was many. "I don't know about you, but I'm getting out of here, nya." She commented as she began to run towards another end of the room. She was about to open the door when she realized that the person still didn't move. Turning her head around, the male was just standing in place like a statue. Sighing to herself, she ran back and grabbed the boy by the arm and began to drag him along.

"Come on! You don't want to get caught by these devils. Trust me, nya!

 **(Time Skip)**

A newly reincarnated devil just beat the crap out of a fallen angel that had passed as his girlfriend and killed him after just because he seemed like a threat to her kind as well as faction. She then tried to use another innocent girl that had been exiled from the church to take her sacred gear to make herself powerful, sacrificing the outcasted maiden. But she was quickly stopped by that devil who awakened and was strengthened his sacred gear.

The master of the boy came back with some dark feather to show that fallen angels that her allies were destroyed by her. As she moved her red hair from her face, she prepared a spell to kill that fallen angel. The young Devil who had just been resurrected didn't even raise a single finger, but an unreadable expression was worn on his face as he looked up through a window of the church they were in.

After destroying the fallen angel, the crimson haired devil gave the sacred gear she had stolen from the little blond nun. Not just because of that, it didn't mean the blonde girl would stay alive as the gear was a part of her that was stripped away before. She then reincarnated the nun as her bishop. The young devil was happy to see that his friend was once again alive, crying tears of joy.

A young man was observing their movement from one of the broken windows, somehow not being noticed as the events unfolded. He was wearing the same clothes as almost every devil that fought that night in this church, which was some sort of school uniform for the male gender. After seeing the girl being reincarnated, he left towards his house. It's good thing that he didn't have a shift for his part-time job.

Steadily, he walked down the streets. His speed was slow. The sluggish pace even caused him to lag behind the passing group that was just at the church despite his head start. Even so, he kept an eye on them for a few more seconds before turning on the sidewalk. He finally arrived at his home. Opening his door, he went directly to his bedroom.

He opened the door of his resting chambers to find older woman who had a two tails and cat ears on his bed reading a book. She was almost naked as her black kimono seemed to be almost undone. She barely looked at him as he entered the room, kicking her legs around in a playful manner. The brown-haired individual sighed at her presence.

"Do I have to make food for you once again?" He asked as he quirked an eyebrow in her presence while staring at her. It was obvious in his voice that the girl's presence was a bit annoying.

"Can't you be a little nicer to me, Tuna-kun?" She said pouting at his sentence. Kuroka rolled onto "I thought we were accomplices, nya?"

"I am already returning your favor by watching over your sister." He deadpanned as he sat down in the chair next to his desk. "Anyways, are you going to talk her or just continue to let her hate you for absolutely no reason?" He then asked, folding his arms and staring, expecting his answer.

"You know why." Kuroka stated, looking away. "By the way, you really changed Tuna-kun. Especially with your hair. I would have never thought before you could tame such spiky hair." She said smirking. It was true though. Tsuna's hair still had a bit of a spike to it, but it had been flattened slightly and there was a bit of a slim mane growing down from the head to the bottom of his neck. "But it kind of makes you more handsome, you must really have a lot of fangirls at that school, nya."

"I don't care about that. It's annoying, but it is apparently useful to get a better salary at my job." Tsuna scowled slightly as he brushed a hand through his now straight hair. "When I looked at my hair back then, it only made me remember of that past. Now I don't have to remembered their betrayal every time I look in the mirror." He said as his eyes flashed an orange while burning a dark black.

"It's weird that the devils in the school didn't notice your presence. You must really be good as hiding your presence especially because of your popularity, nya." Kuroka said smirking as she looked at him when saying the word 'popularity'.

"That's the teachings of the world's greatest hitman at work." Tsuna said in a matter-of-fact tone. "Besides, my popularity is only due to my grades and nothing else. I have no interest in making friends that would eventually... betray me." He said with a sigh and a tone that mixed anger and sadness together in his voice making Kuroka frown at what he said. She kind of wanted him to go to this school to open himself more but even after all of this time, he didn't open up one bit. "Do you have any other purpose to come to my bedroom other than taking my food?"

"I might want to pass an enjoyable night with you, nya." Kuroka said winking, showing more of her body while stretching her back in a rather seductive way. Tsuna didn't spare a glance as he began his homework. It took time, but Tsuna eventually was unaffected by these sorts of actions Kuroka would constantly do. Teasing him was apparently one of her hobbies. It was almost some sort of competition between them to see if she could Tsuna to at least fluster a bit.

The Nekomata nearly succeeded every time she would end up playing with herself right in front of him.

The first time that happened, Tsuna learned that she didn't wear underwear at all.

Kuroka sighed knowing how the boy was. He wasn't really fun to play with right now but she promised herself to help him heal at least a little bit.

She knew his past and the reason he was like that. He saved her and her sister, she at least owned him that. Tsuna was a broken young man who didn't want to serve or boss anyone. He was lonely but he would never let anyone approach him. She knew that in school, people called him the lonely knight who had perfect grade. Well, she knew that it made girls wanted him more as he got few letters of confession each week, which he refused sometimes brutally, sometimes a little more gently, which only made the girls wanting him more. That kind of annoyed him to no end. Scratch that, it did annoy him to no end.

"So what do you want this night?" Tsuna asked with a sigh her common guest as he knew she liked how he gave her his food. There was no point in chasing her out. He just didn't want to deal with the headache that came when forcing her to go away.

"It doesn't really matter as long as it is fish." Kuroka said as she was snapped out from her thought as she imagined the delicious food she was going to eat. "By the way I didn't know that you owned that kind of book, nya." as she turned her attention to the book she was reading and found under his bed. It was some sort of graphic novel of very... 'adult' things.

"I borrowed this book from the stupid perverted trio to make sure that the girls would leave me alone, which didn't really work. It only made some of them more aggressive." Tsuna groaned he closed the book he as working and stood up to go to cook the food. "Seriously, what kind of hormones are these girls filled with?! Back in my day-" He cut himself off, realizing what he just said.

"...You totally sounded like an old man there, nya~." Kuroka sang, giggling a little bit.

"Shut up." The brunette grumbled.

Tsuna went to the kitchen to make the food for the two of them. They then ate the food together in silence. Then they went to bed. Kuroka slept into the same bed as him after they both took a shower to clean themselves where Kuroka cleaned his back who did the same thing for her. He didn't really mind it all, but he just at least wondered if these were really ways for the female to turn him on.

The next day, Tsuna awakened his self at his usual time as he prepared his lunch and made some more food for once Kuroka woke up. He left his house, not his home. it would never be his home without that person's sweet voice always greeting him. He murmured "Ittekimasu."

Tsuna walked up to his school, not taking notice of the girls around him fanning over his presence, and the boys glaring at him. He couldn't care less about people's opinion about him. They could believe whatever they wanted. He didn't just care. He wanted to be alone.

Tsuna looked around him to see the famous perverted trio as two of the idiots seemed to scold their friend who had become a devil a few days ago. The brunette mainly took note of the new devil since that boy had joined up with that Occult Research Club where Shirone was.

He had a normal day as his classes went with any events as the teacher gave him his tests back who all had 100 on them. He was known as one of the best students of their year. The only person who had a rivaled him grade-wise was Rias Gremory. He had to admit, that girl was a really gifted person as well as a great king and person towards the members of her peerage. She was also great with her magic as it was sometimes hard for him to spy on her without them realizing it due to his own flames sometimes reacting to it on instinct.

Tsuna didn't really cared about her greatness, she was for him a person that needed to use the power of her peerage for her own freedom. He could tell that she would need it in the near future as he could see that he wasn't the only one spying on them. There was a strange looking bird that was perched on the window of their ORC room. Narrowing his eyes towards the creature, the odd creature looked like a baby phoenix. Tsuna was half tempted to snatch the bird and crush it but didn't want to risk letting his presence become known. Taking a guess, that bird would have belonged to the Phenex family. Their son, Riser Phenex, was actually to be Rias Gremory's fiancé if Kuroka gave such information correctly.

He wondered if that Riser person was going to be a trouble or not. Seeing the potential of Rias' pawn, they should be able to win a fight and disengage Rias' engagement. He shouldn't need to do anything. He wondered why he felt the need to interfere. He only agreed to watch over and do nothing else.

He promised himself to never become attach to another being to make sure he was never betrayed like his old precious friends did to him. While he trusted them, and was ready to give his life for them, they gave up and surrender his life to his enemies without any doubts. He crushed the soda can that he was holding as he remembered their betrayal.

 **Hope you like it. Please review, favorite and follow. This story is also due to the help of NonaryNathan999.**


	2. Chapter 2

**I do not own Katekyo Hitman Reborn and High School DxD. I only own this story.**

If Tsuna could be honest, he was getting rather bored of watching the peerage that Shirone/Koneko resided in. Mainly because of that pervert and all his actions being the constant performance his eyes had to witness for a while. Who could believe he would go with his friends into the girls' locker room, as they locked themselves into a locker to watch the girls changing. That sort of action never worked in fantasy, and it will never work in reality.

It was actually a bit risk to keep his eye on the members of Gremory's peerage, especially since it was Koneko who had a hearing and a smell heavily sense experienced and intense. Tsuna kind of smiled when he saw that Koneko noticed quickly that they were spying on them and unrevealed them to the girls who had their time punishing them. It was certainly amusing to see the smaller girl practically rip off the locker doors.

Tsuna noticed the emotion that took over him, quickly turning those upward lips into a neutral gaze. He distanced himself from them even more seeing that that idiocy was contagious. He didn't want to become the same as that idiot devil. He still watched the tennis match between the both high-up peerages in the school. He sighed at the rather stupidity and perversion of the students of this school. He couldn't even believe that at his time as a normal teenager, his classmates were way different. They were ignorant, bullies, and eccentric people but he couldn't believe they were this way.

Tsuna then began to spectate a dodgeball match between both peerages because the tennis match had ended up in a draw as they used magic and destroyed their own tennis rackets. It still turned out as a war as it seemed that Gremory and Sitri still decided to use magic once again. He sighed to himself at how this was possibly one of the more pointless moments of his life. Maybe he should just stay at home and spy them using that 'flame'. At least he could do his homework while spying on them.

Tsuna walked back to his house, thankful for the fact that next week or so Kuroka wouldn't be at his house. He would have finally sometime alone. He didn't mind her presence much, but she could be sometimes trouble. She wasn't really a problem when he slept as he sometimes missed the warm of another person, plus he didn't mind her purring in her sleep, not that he would ever admit that. Despite his rather dark, cold attitude, that didn't mean he was emo and hated everything.

He watched the Occult Research Club as they went to get a familiar for Asia or Issei, as it seemed you can only get a familiar once every full moon, or something like that not that he really cared. He just knew that Koneko got a small cute kitten. Tsuna wanted to hit his head against his desk as he saw the scene with the smile. The brunette couldn't believe the idiot that he was. That sadistic training from Reborn was probably affecting him a lot more than he expected. Well, to feel good one must pay a horrible price.

Everything was getting in some sort of disturbing rust events until someone stronger than any person he ever met in the school came into the Occult Research clubroom. The one Kuroka characterized as the strongest queen, Grayfia Lucifuge. Tsuna found himself slightly shivering at her presence as he observed her arrival, despite him not even being in the same room. Frankly it wasn't really her presence that sent the small chill down his spine, it was the way that she looked towards where he was observing them with that 'flame'.

He wondered if she truly noticed him, this fact would make her very dangerous. Tsuna decided to stop observing them as he could guess what was going to happen and he didn't want her to trace him down if she, by chance, noticed him.

That's when the small headache came in. Those 'flames' really did have their great uses. The only problem was that when it actually came down to using them as actual holes in reality. Being able to form one opening near yourself is completely fine. However, the coordination's of the place where your next opening would end up to be was more difficult. More so since that one rip was right out of his line of sight with a constant source powering it.

He decided to go to his part-time job as a butler for the sort of Host Club. His popularity always helped the café as it always made the café full with his fans, be it female with a surprising amount of males. The other butlers were nice enough to help him in the time in need but never tried to befriend him more than he needed to. It may also be because they were all a few years older than him. Or that he sometimes slipped away from their attempts.

Tsuna came back after being forced be at least a little nicer to his customers who were sometimes crazy fans. It was not his fault that they constantly dodged his questions related to orders. Not only that, it also turned into a full blown one sided conversation. To Tsuna, he couldn't decide if it was he who was talking to a brick wall or if he were such a solid surface who responded back incorrectly.

He prepared some food for himself as soon as he went into the kitchen. Weirdly enough, he prepared some fish as he was used to Kuroka's presence and unconsciously made too much food for himself. Perhaps he was a little too used to that female constantly visiting him from time to time now. He didn't really know what to do with the food. Maybe he should keep it for tomorrow but he couldn't use it as a bento since he didn't have school tomorrow. Well, there is also the term called leftovers.

A magic circle similar to the one Gremory's uses suddenly appeared in front of him in his kitchen. The previous person he saw at the ORC who made him retire from spying was right from him. A person who could possibly kill him in mere seconds if she got serious was just a few feet away from him. Well, frankly he didn't know how strong he was or if he could even stand a chance against her. But he knew that she could make his wish to make him return to where he belonged come true. His wish was to return to the dirt.

It's not that he would willingly throw himself into death though.

Back to the matter at hand though, if she began to attack, he at least had to make sure he was prepared for something. However, she bowed in front of him as she arrived. Not knowing what to do he bowed back at her. She spoke her first words to him: "It is nice to meet you, Tsunayoshi Sayake."

"It is nice to meet you too, Grayfia Lucifuge." He replied back in politeness. "Are you hungry? It looks like I have made too much food for myself." He said to her as he remembered what the most important person used to say to him. But still, to make sure he kept his hands behind his back as they were coated in the orange flames he was used to with a coat of darkness.

"Thank you very much, but I am on duty. I cannot eat during work. It would go against my duty as a maid." Grayfia told him with a emotionless face as she bowed back at him to apologize for not being able to eat despite his offer.

"I don't really want the food to go to waste, it is one of the lesson my mother taught me a really long time ago and since I probably won't live to see tomorrow. So please make sure it doesn't go to waste." Tsuna said not looking a bit frightened at the mentioned of his death, he only was sad when he mentioned his mother.

"Do not worry, Tsunayoshi Sayake. Or should I say the reincarnation of Tsunayoshi Sawada, Vongola Decimo, accomplice of Kuroka's escape. I only came to see why you were observing Rias-sama and her peerage. If you became a danger to them, I would need to take action to protect her." She said raising her demonic power dramatically to threatened him, but quickly she lowered it returning to her normal level which was still high. "But I think it isn't the case. My king doesn't think so also as we guessed that you are only here because Kuroka asked you to keep an eye on her sister as your identity isn't really known through the Devil's world, am I right?"

"You may be right, and what would happen if it was the case?" Tsuna asked nonchalantly not really caring about the conversation but still interested in her attention as she didn't want to kill him. She was kind of friendly which seemed to be weird as due to the Devil law, he was a rogue devil and should be kill before he becomes a menace to the devils and the humans and start attacking both of them to feed on their power. He already had several locations on his mind for escape as a patch of black was right under his foot just in case.

"Unlike Kuroka, whom existence and crime are quite known, your existence is notified to only a few who looked at that man's work and found what he was trying to do, so your crime hasn't been known so you aren't guilty of anything in the eyes of my king." She said without a lot of emotion as a first-class maid would.

"So let me rephrase my previous question, why did you came here for?" Tsuna asked with a sigh, wondering even more why she needed to point that he was found innocent. He finally dispelled his flames while scratching his head.

"My king just wanted to let you know that we know about you and that if you ever tried to hurt his sister, you will regret it." Grayfia said once again in intimidation. "And also that he would be thankful if you ever saved his dear sister and her peerage from a threat too big for them to handle."

Tsuna fought the need to face palm in front of the Maou statement, which was threatening and possibly thanking him at the same time. He questioned himself if Lucifer was right in his head, but he decided to not bring such subject that would probably cause an incessant list of the problem with that Maou. "Is that all?" He asked with a raised eyebrow.

"Yes, for now. My king can be... odd sometimes like that. He decided to keep your existence secret for now until you are deemed too dangerous to be left alone. Next time, my king will come himself." She said as she left in the same magic circle she appeared through, but right before she left, she turned to him and said "By the way, Rias-sama and her peerage went to train for their oncoming raking game against Riser-sama's peerage to decide what will happen with their wedding, so they won't be at school for quite some time. But everything should be fine so don't worry about Koneko-sama."

The devil couldn't resist the need to facepalm, and did it quite hard. Tsuna decided to go sleep as he didn't really know what to think in front of the scene that just happen. Tsuna trusted that woman's word as he decided to not investigate the Gremory's peerage. He may check on them one time this week. But he would definitely find a way to watch the fight to see the strength of that peerage.

 **(Time Skip)**

Tsuna was quite surprised by the evolution of the young devil, he had increase his power enough to hurt the heir of the Phenex Family. The rogue Devil didn't give the young perverted devil enough credit and courage to pull what he did. To sacrifice an arm to hit the Phenex with a cross and gamble the fight with some holy water was impressive and quite clever for a pervert, especially after declaring in front of everyone that he claimed Gremory's virginity.

It seemed as he continued to observe the ORC, he quickly realized that the pervert idiot was assembling a harem. Since he saved Asia and Rias, he would say that it can be normal for them to fall in love with him, but he didn't expect the S queen to become interested in him. He didn't think that Akeno would also be a M as she was already a great S. She would be a hard person to deal with.

Tsuna was surprised by the presence of two holy power near the school on that day. He couldn't believe that such strong presence would come towards the school filled of two different devil's peerage. He went to see what was happening and saw two girls hiding their presence. He saw that the presences weren't from the two girls but from the presence from each of their weapons.

Tsuna decided to observe more those two newcomers, after a few days, he understood that one of them were linked to the perverted devil while the other disliked the reincarnation of the outcasted nun into a devil. He also understood that the Prince of the school also known as the knight of Gremory had something against holy swords because of trauma in his past with the church.

After continuing observing the peerage and the two church members, he noticed that Kiba had been through a human experiment to make exorcist able to hold holy sword. Tsuna was getting angry at that fact. He always hated human experiments. Nobody deserved such treatment especially innocent children. He wanted to interfere to punish those responsible for such experiment. Even if he hated Mukuro as much as his other guardians, no one ever deserved being submitted through those experiments as well as his friends.

Tsuna still enjoyed seeing the perverted idiot being punished for disobeying the order of their master. He may have a S side that could satisfied his feelings. He didn't want to admit but he kind of understood why his tutor took great pleasure at seeing people in pain.

Tsuna noticed that acquaintance of the perverted devil was being attack by the same exorcist that almost tried to rape the new bishop of Gremory. He felt himself obligated to help her as he couldn't let someone die in front of him. No matter how hard he tried he couldn't get rid of his sky attribute and so his good natured and his humanitarian side.

He used his flame to appeared close by the fight and before the rogue exorcist could deal anymore damage to the poor girl who had most of her clothes teared down, he leapt into the air while spinning around. With his leg outstretched, his foot kicked the rouge exorcist's arm and caused them to skid away.

"Ahahaha! Another piece of fucking scum came in my way!" Freed yelled, laughing and licking his blade. Irina who already was hurt a fair bit and looked to see who helped her. She saw the male uniform of Kuoh Academy with a young man quite handsome with brown straight hair who seemed to have some of it rebelling be a little spiky. He gave her his jacket to hide her state of undress silently, which made her blush and accept the vest.

"I didn't know that rogue exorcists were as perverted as devils." Tsuna said glaring at the exorcists as he noticed from the corner of his eyes the familiar of Gremory. Tangling his fingers while stretching his arms, he rolled his neck and released a few loud pops.

"I am just punishing that girl for following the wrong leader." Freed said as he behaved like his usual perverted self. Tsuna had a hard time containing himself from not burning the hell out of that person. "Plus, you shouldn't insult those who follows no one, right shitty rogue devil?" Irina was surprised by the information. From what she knew from the church, rogue devils were worse than rogue exorcist as they began quickly insane and feed from humans and anything they find themselves they craved for. But he didn't seem the slightest bit insane or bloodthirsty.

"Why do you stay here? You have the weapon you wanted." Tsuna said not caring a bit about them exposing his identity. He wasn't threatened by that man's presence, but he wondered about his attitude as he should have escape when he had the chance to fuse the swords.

"He is right, why are you still here?" A female voice that seemed to belong to Gremory asked. The three of the people present turned to the voice who really come from a magic circle, it was Gremory with almost all of her peerage except for Kiba who was still hunting the man who was near responsible for the blonde-devil's misery.

Tsuna slightly frowned at their quick arrival, he thought he would have his time to go before they noticed he was here. He should have known anyways. Since he investigated and intervened into the matter himself, he had to endure the consequence. It seemed that the pervert idiot didn't even notice him as he went towards the injured exorcist.

"Irina, are you alright? Asia!" He yelled as Asia came running to heal the injured exorcist.

"Don't worry! I am fine!" Irina said to them but Tsuna could tell she was faking it.

"You shouldn't listen to her. If her injuries aren't being heal in less than a hour, she would probably die." Tsuna said gesturing to the exorcist, making the male devil look back at him and finally notice his presence.

"Lonely Knight! What are you doing here?" Issei asked not knowing what to think of that boy that was an idol for most girls and an enemy for almost every guy. Frankly, he wasn't the only one surprise by that teen's presence. They always found him odd but he wasn't anything else than an excellent student as no magic or special aura was ever felt coming from him.

Tsuna looked a little bored at the situation, they didn't know who he was and what power he had. He bet they didn't even know his origin. Tsuna saw that the situation was under control as the student council president, Sona Sitri showed up. He didn't need to interfere any longer.

He decided to leave without so much as a word as he didn't owe them anything especially an explanation. For the next few hours, he completely ignored every question they had towards seeing that Sona Sitri took the injured girl to a healing chamber. But before he left, the sky changed color into a dark atmosphere clearing saying that fallen angel was coming. He looked back to see a fallen angel with ten wings clearly saying that he was a chief of strong power which would impossible for the two new devils and their peerage to take care. So, he decided to watch and see what happen. Plus, he would take some of his energy to escape this stupid dimension that the fallen angel created.

"Hello, we have never met before Gremory-san, sister of the Crimson Devil. I am Kokabiel." He said quite peacefully but aggressively at the same time. He was emitting a pure aura of confidence telling Tsuna that he could wiped them out in a matter of minutes. "Sona Sitri is present as well as Tsunayoshi Sawada." He said the last part smirking looking at him as if he knew something he didn't know.

"Hello to you too, Fallen Angel's chief. I am Rias Gremory. What is the point of this meeting? It is unusual for a chief to come to talk." Gremory said not flinching in front of the strong opponent. Tsuna was kind of surprised that she wasn't affected by his presence. But he knew that she had some doubt especially the part where he talked about mentioning his real name. She must have heard it from somewhere as well as Sitri.

"I wanted to have some fun around the academy, your domain in this city. Your brother might come to help you if it is too much for you, right? Plus, being able to see the fallen sky once again is a plus." Kokabiel said smiling, no smirking. This annoyed everyone including Tsuna but of course for different reason.

"That would only start another war between the three factions!" Rias yelled as she glared as it was the first concern. For Tsuna right now, he wanted to know how he found out about him and his past. Being to use the turn fallen sky must mean that he knew something about him. Plus, he used the term of again meaning he already saw him in his past life. This wasn't good, he needed to know but at the same time, he promised not to interfere. He would have to wait and find out later. For now, he guessed he needed to wait and see what was going to happen.

While Tsuna was thinking about what he said, he completely forgot about what was happening and didn't hear the stupid monologue of the Fallen Angel wanting to start another war for the purpose of his boredom. He was really stupid, he wondered if he actually knew about him. He just seemed like a common battle freak that just wanted fight to kill and not for any other reason, maybe also to show the superiority of his faction.

Where was this odd hit of nostalgia coming from? Oh right, that marshmallow-loving albino Byakuran. Both of them seemed to smile and smirk a lot to an end where Tsuna actually could swear their faces were frozen in such positions. They almost did whatever they wanted because they were bored. Heck, Kokabiel here even has wings like Byakuran, what were the odds in that department?

He understood that the fanatic decided to fight in their own school because it was the territory of two great family, the Gremory and the Sitri. Nobody could deny that it wasn't a good idea for starting the war. The crazy Fallen Angel continued to ignore his presence until he looked at him directly and said: "Fallen sky, you should witness it all. You might then understand why you sank this low to have to rely on that stupid rogue Nekomata devil, Kuroka, to run after killing your king!" This last part made most of the devils, except the recently reincarnated looked back at him as they all knew who that person was and what was her crime especially against the kitten.

"How do you know about that?" Tsuna said lowly and dangerous with his eyes hidden by his bangs. If he knew about that, what else did he knew about him?

"Well, I know almost everything about you. The Fallen Angels has been taken a great interest as you grow to become one of the strongest human who ever live. You needed to be taken care of." He said the last part smirking. "You were then reincarnated by a stupid devil who you killed without any remorse and escape with the help of that black cat. Should I add something to prove that I know you, fallen sky?"

"What do you mean by to be taken care of?" Tsuna asked very low and dangerously, most of the people around felt the temperature rise enough to make them begin to sweat at the heat that came from the Lonely Knight.

"Ahahaha! You will have to find me to learn more." He said as he threw light spears at them to make an escape. Most of them moved to dodge the attacks. But Tsuna didn't move as he used his flames to destroy or make the spear disappear.

"If that's the case..." Tsuna gripped his hands tightly to make fists. The sky attribute covered his forehead and arms like normal, but this time the rest of his body was coated in the dark flames that were as transparent as black ink. "The hunt begins."

 **Hope you like it. Please review, favorite and follow. This story is also due to the help of NonaryNathan999.**


	3. Chapter 3

**I do not own Katekyo Hitman Reborn and High School DxD. I only own this story.**

There was no need for an epic chase.

There was no need to find Kokabiel.

That Fallen Angel pretty much just headed straight towards Kuoh Academy, taunting each Devil that followed him with a typhoon of mockery. Everyone had their attention up towards the sky though, eyes trained on the nuisance that appeared. Anticipation of battle grew within them as they prepared themselves for a fight.

All of them refused to die in this kind of situation. Most of them were there to protect the school they take classes in and be in together with their friends. They were going to live on and fight for the next day of their lives.

Tsuna nearly sighed to himself as these situations of late had been bringing up many memories, whether they were good or bad he couldn't exactly state. These moments reminded him of the good times, but it made him feel torn within. His mind was being split into two, unable to decide if he should be at peace or continue to live with hatred and sadness.

But all of that was thrown out of the window when they arrived to the school. As soon as they set foot into the academy grounds, there was a bright light shining from the ground and reaching towards the sky. Four objects that looked like blades were in a compass-like pattern while an even brighter glow surrounded them. All the meanwhile, a single man stood within with a maddening smile.

"It's time to make these four holy swords into one." The male snickered. His outfit identified him as a priest of some sorts, most likely classifying him into the exorcist faction. His eyes were hidden behind a pair of glasses, but one could easily tell it was a manic look with all of his teeth being shown with his intense grin. He also was a little on the portly side, having a bit more fat than muscle.

"How long until it is done, Valper?"

Hearing this, everybody looked up to see that Kokabiel was sitting right on a chair with a glyph underneath. The very platform supported the furniture up in the sky under the moonlight to reveal the Grigori sitting in a position as if he were watching a movie.

…Sure, throw Xanxus into the mix as well! That elite assassin one told the boy about the future events of how the adult took on two fake Funeral Wreaths in the future without breaking a sweat… without even getting off of his chair while he was at it! Honestly, this is just bringing up even more memories of the past.

"Alright, Kokabiel," Tsuna tightened his fingers into fists, cracking his knuckles in the process. Stomping on the ground, he slowly raised his hands and made his positioning point towards the Fallen and in the opposite direction. "Enough running like the coward that you are. You're going to tell me everything I want to know or else I'm going to burn your entire body like a steak."

"Why the rush, Fallen Sky?" Kokabiel smirked, bringing up an arm that was resting on his chair and placing his fist against a hand. "Don't you want to first know what sort of plan I have in mind? Think before rushing in without any knowledge like you did in the past?" He then took in a sharp deep breath, clearly faking a moment of shock. "Oops, I guess you weren't supposed to know that." The sentence was sarcastic, with a grin proving the point even further. "As for you Gremory," He turned his attention to Rias' faction. "Is your brother coming? Or perhaps Serafall?"

"We'll be the ones to face you in place of my brother and Leviathan!" Rias answered defiantly with a loud shout.

Kokabiel merely raised his arm in response and made a throwing motion. Not a second passed when a giant spear of light collided with the gymnasium of the academy, completely destroying the building as if it was nothing. "How dull."

"Take this, Kokabiel!" Rias exclaimed, firing a large beam of magic towards the Fallen Angel. But the sitting male did nothing to even attempt to dodge. Instead, he raised the hand that threw the spear and stopped the attack as if he were catching a ball before tossing the projectile up into the air.

But at the same time, the Fallen Angel grabbed a wrist that attempted to slice his arm apart. "Oh? And now a new ant shows up trying to hurt me? How hilarious." He mused before throwing the arm towards the group of them. The owner of the arm turned out to be Kiba as the blonde was sent hurling towards the dirt.

Tsuna meanwhile had his eyes set on Valper. Rushing forward, Tsuna's speed was impressive as he appeared right in front of the man. But before he could lay his hands upon the adult, Tsuna leapt back to avoid a few more spears of light from Kokabiel. "You are a nuisance, did you know that." Valper frowned at the brunette. "You're just like all those experiments I've discarded. Meddlesome things that keep reappearing, no matter how many times they've been put down. Why not just die like them?"

"Shut up." Tsuna growled, rolling his shoulder. Eyeing Kokabiel out of the corner of his eye, he noticed that the Fallen Angel was doing nothing to stop him. Why was that? It didn't matter. "Just wait until I get my hands on you."

With another leap, Tsuna lunged towards the fat priest.

It then felt like something was burning into his flesh as he suddenly dropped to the ground.

Growling, Tsuna forced himself up and moved forward once again. This time, some sort of barrier stopped him from wringing the air out of the man. Looking around furiously, he eventually saw that four Excaliburs that the church was talking about that were stolen.

"Ah, so it looks like your words were correct." Valper commented, looking up towards Kokabiel.

The Fallen Angel meanwhile was just watching Rias and her peerage fighting a giant three-headed dog. It apparently was a lot more threatening than it sounded since it was keeping everybody occupied. Even one of the two exorcists that were meant to retrieve the fragments of the Excaliburs was fighting with them.

"Of course, the Excaliburs can create a barrier of holy light easily. One just needs the knowhow." Kokabiel shrugged his shoulders, as if he had no doubt at all. "But now let's us have a nice chat, Fallen Sky. We have much to catch up on."

Tsuna was too busy grunting under the burning pain while trying to get out of the barrier that this Grigori had just mentioned. But no matter what he did, he couldn't escape for some reason. He tried to break through the barrier with his fists, but they bounced off some invisible surface. His flames didn't burn through the barrier. There was no end as he had attempted to fly upwards. His dark flames would dissolve within the light and unable for him to keep a hole open for escape. Like a bug in a cage, he was trapped.

"Now, where should I being?" Kokabiel asked himself as Tsuna was starting to lose his strength. "Perhaps it was when you killed one of my kind."

Tsuna's took in a sharp breath as he quickly looked up towards the Fallen who had just revealed this information. "Your kind?" He asked with narrow eyes.

"Of course, what other race has black wings like me?" Kokabiel questioned. "Where was I? Ah, right, you killing one of my kind. Did you know that it was me who sent them to kill you? What am I saying? Of course, you didn't! The Vongola didn't even know about us supernatural beings. It seems that killed also severed one of your bonds. I shouldn't mention this, but it's funny how you and your guardians can't tell the difference between murder and suicide. One by one, I sent Fallen after Fallen after you. One by one, they would engage you and your guardians. One by one, they would 'die' by your hands. One by one, your bonds would shatter. And then, we come to our grand finale; your mother!"

"You…" Tsuna gritted out, trying to stand up but couldn't due to his body refusing to function properly. "This was your doing?! You're the one who sent all those men to kill me?! You're the reason everybody left?! You're the reason my mom died?!"

"Oh, it was such a tragic tale." Kokabiel sighed dramatically, even bringing his arm up to his face. "The Fallen Sky, all alone, unable to do anything as the corpse of his mother fell from the sky and down to the Earth." His gaze was soon free to look at the brunette who was still lying on the ground while twitching. "What did you feel when that happened? Fear? Pain? Anguish? Rage? Hatred? That everything that you had was taken away from you? That you were abandoned by everyone around you? That your existence had been forsaken?"

Tsuna tried to speak, but the burning sensation was killing him. It felt like the inside of his body was being cooked.

"No, no, wait, I got it." Kokabiel smirked. "The feeling inside that you were sinking, sinking into something you could never get out of, that you could never escape from. No matter how hard you try it continued to pull you under, latching onto your soul, dragging you down. It feels like you are drowning in your own thoughts, suffocating under the weight of your own emotions, and when it is over, there is nothing left of what you once were."

With his head rolling to the side, it was then that the brunette noticed everybody was listening in on the conversation between he and Kokabiel. How much did they listen into? Rias and Akeno stared at him with wide eyes. Issei's jaw dropped to the ground. Kiba was delivering a full-blown glare towards Kokabiel. The cat Tsuna was told to look after had an unreadable look, but he knew she felt sorry for him. Xenovia meanwhile wore pity. Asia looked like she was going to cry.

"Kokabiel, you bastard!" Issei roared as he ran towards the Fallen Angel, forgetting that the man was floating in the air on a chair.

Only Kiba, Asia, Koneko, and Xenovia ran towards Tsuna while everyone else went straight for Kokabiel.

Issei was constantly jumping into the air like a grasshopper, doing his best to land a blow onto the Fallen's face. Akeno fired bolts of lightning as if she were a Greek God. Rias was flying through the air, trying to find blind spots of the Fallen Angel to land in the perfect shot.

Meanwhile with the brunette, Kiba furiously ran towards Valper to confront the chubby Christian-man. Koneko and Xenovia were busy trying to get past the barrier, using nothing but brute force to attempt to shatter the shield. Asia however seemed like she was trying to get through as well, hands raised to heal the brunette.

Tsuna's eyes were dull as the pain continued to spread through his body. Why were they trying to help him? He did nothing for them at all. What? Just listening to his past made them all want to help him out? Just like that, they would come to his aid?

Vision began to turn black for the boy as he felt his conscious drift away. He ignored the shouts from those surrounding him.

Wasn't this what he wanted in the end though? Death and to be able to rest? There was nothing left for him in this world. There was nobody for him to live for. There was nobody that he cared for. Why did he still fight to live? Why not just let go and sleep already?

But then he heard something…

It was a sound…

…A voice…

Despite all the shouting… it stood out to him…

Prying his eyelids open, they were squinted but still could managed to make out something. It was a girl… with black-cat ears…

Tsuna could easily recognize that look anywhere. It was blurry. Yet still, he could make out those sandals and that kimono.

"Kuroka…" Tsuna whispered as he found himself staring at the Nekomata. It was odd though. No one else seemed to notice her yet she was right on top of him. Why was she here in the first place?

'Kuroka' only continued to smile at him, straddling him in an almost exciting way. Her legs were spread out so that she could take a comfortable position right on top of his pelvis. She held a mischievous smirk while touching her lips with a single finger as if in thought. Soon enough, she broke out into a smile. Standing up, 'Kuroka' held her hand out for the brunette to grab.

Tsuna reached for the limb. But no matter how hard, how badly, he tried to touch the hand it constantly slipped out of his grip. With all the strength, he could muster, he attempted to grab her aid of getting him back off the ground. But his own fingers went through her palm again and again.

He wanted to die… but why was he reaching out towards someone who was alive? Someone who had the desire to constantly live? Should he just rest already? Or should he stay? Leave? Or stay? There was death, a state where he didn't need to worry about anything anymore. But there was still life, one where he would constantly go to school to re-learn everything he knew, be harassed by fan-girls… having a single face swing on by on a nearly frequent basis…

" **How selfish of you**."

Tsuna's world soon began turning black once more. But his eyes were not closed. They were still wide open. It was odd. He was surrounded by the black abyss, yet he did not feel a thing.

But where did that voice come from?

Looking around, he eventually saw something… someone.

They wore a semi-heavy black armor and a muscular body suit with orange highlights streaking around. Dark ballooning hakama pants were worn on the bottom. Long, black hair was loose and ran wild, untamed and free. Shoulder pads looked like they were faces, white jaws clenched as if biting down and orange eyes glaring daggers at whoever stared at them. The face seemed more like a helmet or a mask, sharp teeth just like the shoulders like a shark about to feed. Clawed fingers dangled from its hands and arms, constantly rolling as if ready for a fight.

"…Who are you?" Tsuna asked, slowly slipping into a fighting position. "…What are you?" He continued to question.

" **Ha**." The being scoffed in amusement. " **It is always fun watching you humans constantly satisfy your curious natures. Yet it is questions that you must rely on rather than creating answers for yourselves**." Folding its arms, the being stared at Tsuna. " **I am Zen no Sentoki**." Its voice was deep, as if speaking from the back of a throat.

"Zen… no… Sentoki…" Tsuna said slowly, wondering what was going on right now.

" **A God is perhaps a much more specific term for a kind like my own**." Zen no Sentoki simply stated, continuing to look at Tsuna. The face the helmet had looked like it was going to consume the brunette.

"Where is this? What do you want from me?" The Fallen Sky raised his fists for a fight, but then blinked and realized that this new being had just disappeared.

" **How pitiful that you do not recognize your own mind**." The being that claimed to be a God simple commented. " **I do not want anything from you. But however, it is you that wants something from me**."

"Something from you." Tsuna stated, slowly turning around. It was odd how his body felt light at the moment. Like he had sustained no injury in the slightest. "We've never even met."

" **That does not matter**." Zen no Sentoki commented. " **I have no choice in this matter at the moment. If you die, I suffer the same wretched fate**." Before Tsuna could speak however, the being slammed its hand across Tsuna's mouth and gripped it tightly to prevent the brunette from speaking. " **Use your brain, boy. Do you not find it strange that the Fallen targeted you in the past? That it was just for your position due to being the Decimo of the Vongola? No, it was because of me**."

Because of this being? What did Tsuna get himself dragged into this time in the past? Wait… Kuroka did say that Fallen mainly targeted humans because of their jealously. What they were jealous of confused Tsuna at first. But then the Nekomata easily explained it to him and it clicked.

"…A Sacred Gear…" Tsuna said, his hand being muffled by Zen no Sentoki.

" **Have you began thinking now?** " The enigma asked, slowly taking its hand off of Tsuna. " **Good, now is the time that you come present your power to the outer world**."

Taking a couple of moments to process those words, Tsuna looked over to the being claiming itself as a God. "Wait a minute… I've trapped within a barrier created by the Excaliburs with their light already pretty much killing me in the process! How the hell am I supposed to get back up?!"

" **Fool.** " Zen no Sentoki turned around and began to walk back into the darkness as Tsuna's vision began to turn bright. " **Why ask when you already know how to?** "

It eventually was too much, light consumed the dark world and Tsuna found himself back in reality.

He tried to move, but his body refused to work once again. The barrier of light was still functioning and his body was being burned by the holy element. Tsuna knew that he had to do something, but he couldn't. If only he had something that could help him get back on his feet. Something to heal him…

Like the ability, Asia had.

Suddenly, his fingers twitched… then his arm…

Looking towards the limbs, he then noticed an orange light covering said limbs. It tingled slightly, but he could eventually move his entire arm like it had never been hurt in the first place. But… how…

He could save that question for later. He attempted to perform this act on the rest of his body immediately. Seeing how it was a success, he leapt to his feet and looked right at the Excaliburs that were containing him.

"I **have** strength…" Tsuna muttered to himself, ignoring how everyone was staring at him as he was just on the ground and suddenly up like it was nothing. "… **I** have **power** …" His arms soon opened wide, as if ready to embrace something. "…I **shall** soon **have everything** …" His eyes were in a trance, as if he didn't know what he was saying.

Darkness took over his entire body, leaving nothing but a mass of black flames. However, it looked like light was being absorbed from his surroundings. Yellow streams were diving right into the mass without a second thought. "By **my hand** , I **shall forge** my **own path** and **deny all that try and stop me**!"

A pair of hands suddenly popped right out from the black blob wide open. Orange and black fire wrapped around them, eventually melting into a pair of sharp, clawed gauntlets that resembled a combination of a monster and dragon. Soon, the four Excaliburs suddenly began to spin around, flying straight towards the metal limbs and become absorbed into them.

Clenching his hands into fists, the black fire exploded outwards to reveal Zen no Sentoki's body. But Tsuna's voice was there yet warped.

" **Behold, Takegami – God of Military Arts!** "

 **Hey guys, NonaryNathan999 here with this specific chapter. Not much really happened… but after a week of stressed out studying with a final being finished just before writing this chapter for 3 hours straight with no breaks and worrying if I passed that final or not, making me wonder if I managed to pass or fail the level… It's pretty taxing.**

 **Anyways… there we go. A chapter… its… it's something… yeah… Yeah. Yeah! YEAH!**

 **Hope you like it. Please review. Your choice to follow or favorite. This story is also due to the help of TIgrun.**

 **No flames please.**


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